<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box1 {
            width: 200px;
            height: 200px;
            border: 1px red solid;
            box-sizing: border-box;
        }
        .box2 {
            height: 100%;
            background-color: aqua;
        }

        .box3 {
            width: 100px;
            height: 200px;
            border-top: 1px red solid;
            border-left: 1px red solid;
            border-bottom: 1px red solid;
            background-color: aqua;
            float: left;
            box-sizing: border-box;
        }
        .box4 {
            width: 100px;
            height: 200px;
            border-top: 1px red solid;
            border-right: 1px red solid;
            border-bottom: 1px red solid;
            background-color: aqua;
            float: left;
            box-sizing: border-box;
        }
    </style>
</head>
<body>
    <div class="box1">
        <div class="box2"></div>
    </div>
    <div class="box3">
    </div>
    <div class="box4"></div>
</body>
</html>